MCP seems to not have an entry for Sat-Yr9's unfortunate lackey Nigel Frobisher. He appears in

XCAL 1
XCAL 2
XCAL 9
XCAL 11
XCAL 12
XCAL 13
XCAL 15
XCAL 21
XCAL 27
XCAL 32
XCAL 55
XCAL 56
dying in the last of these. There's also an alternate reality version of him in XCAL 14, just in case anyone sees him listed online as appearing in that issue and thinks I overlooked it - different Nigel Frobisher.

Additionally, the current listing for Vixen, the crimelord Nigel replaced and impersonated, is incomplete, and has one wrong entry (it is Nigel impersonating her in XCAL 32; the real Vixen doesn't appear).